1. Broadhurst, T. J., Ellis, R. S., Kov, D.C. & Szalay, A.S. Nature 343, 726–728 (1990).
2. Geller, M.J. & Huchra, J.H. Science, 246, 897–903 (1989).
3. Kolb, E.W. & Turner, M.S. The Early Universe (Addison-Wesley, Reading, Massachusetts, 1990).
4. Davis, M. & Efstathiou, G. in Large Scale Motions in the Universe: A Vatican Study Week (eds Rubin V. & Coyne, G.) 439–456 (Princeton University Press, 1988).
5. Raup, D.M. & Sepkoski, J.J., Proc. natn. Acad. Sci. U.S.A. 84, 801–805 (1984).